[antlr-interest] added a lot of lookahead computation notes

[Terence Parr]

Folks, if you're following my thoughts for ANTLR 3 lookahead 
computation and usage during parse-time, you will find my recent entry 
interesting:

http://www.antlr.org/blog/antlr3/lookahead.tml

I think I have a nice way to do generalized LL lookahead (k=1, k>1, 
infinite k) including hoisting of predicates, all in the guise of a 
specialized  NFA->DFA conversion.  In fact, I'm a little frightened I 
have rendered my dissertation old news! ;)  'Course that *was* 13 years 
ago (heavy sigh) ;)

The reason that I am using all of my cpu time thinking about how to 
view lookahead computation etc... is that I smell a vast simplification 
of the process (that will also appeal to theory-wienies).  The simpler 
the perspective, the simpler the algorithm, and hopefully the more 
transparent the ANTLR code will be.  One of my primary goals is 
"obvious code" for ANTLR 3.0.

Anyway, I've tried to write down my current understanding of the 
issues...feel free to comment or whatever (yes, I know there are some 
typos in there) :)  I really think I've latched onto something 
significant here.

Ahhhhhh....I'm never happier than when I'm working on a graph algorithm 
:) :D

Ter
--
Professor Comp. Sci., University of San Francisco
Creator, ANTLR Parser Generator, http://www.antlr.org
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